Temperature controlled accelerator pump



Nov. 14, 1961 1.. c. DERMOND TEMPERATURE CONTROLLED ACCELERATOR PUMPFiled June 11, 1958 W 4 A fw\\\\\\\\\\\\v\\\\\\\\\\\\\\\\\\\ E KWZ M MmM We W w w United States Patent PUMP Lawrence C. Dermond, Rochester,N.Y., assiguor to General Motors Corporation, Detroit, Mich., acorporation of Delaware Filed June 11, 1958, Ser. No.*741,283

' 8 Claims. (Cl. 261-34) The present invention relates to a mechanismfor varying the quantity of the charge of an accelerator pump inaccordance with engine temperature. Inasmuch as an engine requires alarger accelerating charge when cold than when warm, it is desirablefrom economy and performance points of view to provide means whereby theacceleration charge is responsive to engine temperature.

Engine temperature responsive acceleration charge devices are notbroadly new, however, such devices have, in the past, been frequentlytoo complicated and hence too costly to be commercially feasible. It istherefore an object of the present invention to provide a simple andreliable means for regulating the acceleration charge in accordance withengine temperature whereby more eco nomical operation of a carburetor isrealized.

In the present invention a temperature responsive valve mechanism isdisposed within the fuel reservoir in such The details as well as otherobjects and advantages of A the present invention will be apparent froma perusal of the detail description which follows.

In the drawing:

FIG. 1 discloses a carburetor embodying the subject invention.

FIG. 2 is a View along line 22 of FIG. 1.

A carburetor is shown generally at 10 and includes a casing 12 withinwhich a fuel reservoir 14 is formed. An accelerating pump is indicatedgenerally at 16 and includes a cylinder casing 18 within which a piston20 mounted on a rod 22 is slidably disposed. The piston rod 22 issuitably connected -to the accelerator pedal, not shown, so as to causethe rod to move downwardly within casing 18 when the pedal is depressed.

As set forth in greater detail in Patent 2,771,282 Olson et al., theaccelerator pump piston 20 is axially movable relative to rod 22. Afirst spring 24 is seated within casing 18 and biases the piston in anupwardly or charging direction. A second spring 26 seats against awasher 28 fixed to rod 22 and at its other end biases piston 20 in adownwardly direction. Thus as the accelerator pedal is released, rod 22moves tupwardly decreasing the rate of spring 26 permitting spring 24 tomove the piston upwardly. The upward movement of the piston causes aball check valve 30 in casing passage 32 to lift olf its seat 34 whichin turn causes fuel from reservoir 14 to be drawn through a conduit 36into the accelerating pump cylinder chamber 38.

An accelerator pump output passage 40 communicates through passage 32with accelerator pump chamber 38. One end, the left as viewed in thedrawing, communicates with the carburetor induction passage. Assume forthe moment, that the other end 42 of passage 40 is to be blocked. As theaccelerator pedal is depressed, the rate of spring 26 is increased so asto overcome the force of spring 24, moving piston 20 downwardly. Thismovement seats ball check valve 30 forcing a charge of fuel to bedelivered to the carburetor induction passage to enrichen the fuel-airmixture to permit rapid acceleration.

As thus far described, the accelerator pump is of conventional designand forms no part of the present invention except insofar as it combineswith a temperature sensitive mechanism now to be described.

The fuel reservoir casing 12 includes a hollow boss member 44 projectingupwardly within reservoir 14 and the interior of which boss communicatesat its lower end with end 42 of accelerator pump discharge passage 40; Avalve mechanism 46 is disposed within the open end of easing boss 44 andis adapted to permit fuel from the discharge passage 40 to be bypassedback to the fuel reservoir 14 in accordance with engine temperature.

Valve mechanism 46 includes a sleeve member having a flange 50 at oneend thereof adapted to dependingly support the valve mechanism withinboss 44. The sleeve member includes 'a plurality of sections 52, 54, and56 of progressively reduced diameter and the largest 52 of which is openat its upper end and the smallest 56 of which is closed at its lower endto provide a valve supporting sleeve. The largest diameter portion 52 ofthe sleeve member coacts with the interior surface of boss 44 to providea chamber 58 which is sealed from communication with fuel reservoir 14except for a pair of diametral ports 60 formed in sleeve section 56.

A cylindrical valve member 62 is rotatably supported within sleevesection 5.6 through a temperature responsive thermostatic coil element64. Coil 64 is in turn supported at its upper end through awasher-sleeve member 66, the latter being peripherally supported uponsleeve flange 50.

Cylindrical valve member 62 includes a diametral'passage 68 adapted tobe aligned with diametral sleeve ports 60. Valve member 62 also includesa longitudinally extending passage 70 communicating diametral passage 68with sleeve chamber 72 openly communicating with fuel reservoir 14.

The thermostatic coil 64 is adapted to wind or unwind inaccordance withthe temperature of the fuel within reservoir which in turn reflectsengine temperature. As the coil rotates, valve element diametralpas-sage 68 will move into or out of registry with ports 60 in sleevesection 56 to thereby control the quantity of fuel bypassed back to thereservoir 14 as the accelerator pump piston 20 moves downwardly toprovide an accelerating charge to the carburetor induction passage.

Since rotation of coil 64 will cause the same to be lengthened orshortened to a small extent, the diametral ports 60 are made somewhatlarger than valve element passage 68. In this way axial movement ofmember 62 due to changes in the aforenoted coil length, will not effectthe registry between ports 60 and passage 62.

With the engine cold, the maximum quantity of accelerating charge isrequired, therefore, under these conditions, thermostatic coil 64 isadapted to rotate valve member 62 to move passage 68 completely out ofregistry with sleeve ports 60 whereby end 42 of discharge passage 40,is, in effect, blocked, permitting the entire accelerating charge to besupplied to the induction passage. As

the engine warms, coil 64 gradually moves the diametral passage 68 intoregistry with the sleeve ports 60 progressively increasing the quantityof accelerating charge which is bypassed back to the fuel reservoirwhereby the accelerating charge supplied to the induction passage isincrementally reduced in accordance with engine temperature.

I claim:

1. A charge forming device for an internal combustion engine includingan induction passage, a fuel reservoir, an accelerator pump, saidaccelerator pump including a discharge passage means communicating atone end with said induction passage, and valve means disposed in saidfuel reservoir cooperating with said discharge passage to bypass -aportion of the fuel supplied by said accelerator pump to said dischargepassage in accordance with changes in engine temperature, the other endof said discharge passage means communicating with said fuel reservoir,said valve mechanism including a valve element disposed in saiddischarge assage means, and a helically coiled fuel temperatureresponsive member supported within said reservoir and operativelyconnected to said valve element for controlling the quantity of fuelbypassed from said discharge passage means back to said, reservoir.

2. A charge forming device for an internal combustion engine includingan induction passage, a fuel reservoir, an, accelerator pump, said.accelerator pump including a discharge passage means communicating atone end with said induction passage, a boss formed in and openlycommunicating with said fuel reservoir, said boss also communicatingwith the discharge passage means, valve, means disposed in said boss andadapted to bypass a portion of the fuel supplied by said acceleratorpump to said discharge passage. in accordance with changes in enginetemperature, the other end of said discharge passage means communicatingwith saidfuel reservoir, said valve mechanism including a valve elementdisposed in said discharge passage means, and. a fuel temperatureresponsive member operatively connected to said valve element forcontrolling the quantity of fuel bypassed from said discharge passagemeans back to said reservoir.

3. A charge. forming device as set forth in claim 2 in which said valvemechanism comprises a sleeve member supported within said boss, saidsleeve and boss cooperating with the discharge passage means to define achamber, port means in said sleeve adapted to communicate said chamberwith the reservoir, said valve element adapted to cooperate with theport means to control the quantity of accelerator pump fuel bypassed tosaid reservoir in accordance with. engine fuel temperature.

4. A charge forming device as set forth in claim 3 in which thetemperature responsive member comprises a 4 helically coiled elementsupported at one end upon said sleeve and connected at its other end tothe valve element.

5. A charge forming device as set forth in claim 3 in which the sleevemember includes a first portion sup ported within said boss and open tosaid reservoir at one end, asecond; portion of smaHer cross-sectionalarea than the first portion, said port means being formed in the secondsleeve. portion, said. second sleeve portion being adapted torotatablysupport the. valve element.

6. A charge forming device as set forth in claim 5 in which said valveelement includes passage means, one end of said passage means incommunication with the reservoir and the other end of which is adaptedto, register with said port means.

7'. A charge forming device as set forth in claim 6 in which thetemperature responsive member comprises a helically coi-led elementsupported from the open end of the first sleeve portion, the other endof said temperature responsive element being connected to the valveelement to. rotate the same in accordance with engine temperaturechanges to vary the registry between the port means and said valveelement passage means.

8. A charge forming device as set forth in claim 7 in which the portmeans is sufficiently larger in diameter than said valve element passagemeans that the degree of said registry will be unaffected by the axialmovement of said valve element occasioned by changes in length of thetemperature responsive element.

Heitger Apr. 25, 1933 Boyce Ian, 13, 1953

